The invention relates to apparatus for introducing an additive in the form of a liquid or granulated solid into a liquid and more particularly to a container which automatically adds the additive to the liquid on opening of the container.
In a wide number of applications, such as pharmaceuticals for both human and animal use, agrochemicals and other more general applications it may be necessary to release and mix a liquid catalyst or reagent into a liquid before the liquid may be used. Conventional methods involve a user measuring out the liquid catalyst or reagent and then adding it to the main liquid. This may cause problems in that it is prone to human error in the measuring of the amount of liquid catalyst or reagent and may also be hazardous if the catalyst or reagent is toxic.
International Patent Application No PCT/GB96/01803 discloses an apparatus for introducing a fluid into a first liquid comprising a first container (for example a bottle) which contains the first liquid, a bottle top and a second container attached to the underside of the bottle top to form a cap assembly. The second container contains a fluid under pressure. When the bottle top is placed on the bottle the fluid in the second container expands and drives a membrane onto a rupturing spike. The fluid is then released from the second container to the liquid in the bottle.
A disadvantage of the known apparatus is that if the fluid is a dye, for example, there remain residues of the dye on the underside of the cap assembly, since the propellant gas in the second container does not drive out every drop of fluid. Some fluid remains behind the ruptured foil. This means that care must be taken with the cap assembly so that dye is not transferred to clothing, table tops etc.
A further disadvantage of the known apparatus is that the dose of fluid delivered by the apparatus is inaccurate. The second container is filled with the fluid under pressure, and after release an unknown volume of fluid remains in the container and in the dip tube connector, as well as in the dip tube if a dip tube is used.
A further disadvantage of the known apparatus is that it can only be used with fluids and liquids which can be readily expelled through the small ruptured aperture.
A further disadvantage of the known apparatus is that it can only be used to add one component to the liquid.
It is an object of the present invention to provide an apparatus which overcomes one or more of the above disadvantages.
According to a first aspect of the present invention there is provided an apparatus for introducing a component into a first liquid, the apparatus comprising:
a first container for holding the first liquid having an opening closed by a releasable closure, a second container located in the first container, and a conduit having a first end communicating with the second container and a second end communicating with the first container;
wherein the conduit contains an additive which is expelled from the conduit into the first liquid by the entry of the propellant fluid into the conduit on release of the releasable closure.
The conduit forms a dip tube, which serves the purpose of storing the additive product until it is fired by pressure of propellant from the tank or second container into the first liquid in the first container.
Preferably the second container comprises an outer housing and an inner container containing a propellant fluid, the inner container being movably mounted in the housing for movement between a closed position in which the inner container is sealed by the housing when the releasable closure closes the opening, and an open position in which the propellant fluid within the inner container is released from the inner container into the conduit on release of the releasable closure.
Preferably the second container is located adjacent to the opening in the first container.
Preferably the inner container includes a rupturable member and the housing includes a rupturing member to rupture the rupturable member on the inner container.
Preferably on closing of the first container by the closure, the inner container is moved to the closed position and the second container includes a sealing device and when the inner container is in the closed position, the rupturable member is ruptured by he rupturing member and the contents of the inner container prevented from being released from the inner container by the sealing member.
Preferably the sealing member is mounted on the inner container and seals against the rupturing member on the housing.
Preferably the rupturable member includes a fluid port is through which the fluid passes when the second container moves to the open position.
Preferably the conduit extends below the surface of the first liquid in the first container. Alternatively the conduit may extend to a position close to the wall of the first container above the surface of the first liquid, to avoid foaming of the liquid and the creation of pressure waves in the liquid. The first container may be a bottle having a neck, and the conduit may extend to a position adjacent to the wall of the neck.
The propellant fluid may comprise a gas or a gas/liquid mixture. Preferably the propellant fluid is pressurized, to aid expulsion of the fluid from the second container on release of the closure. Typically, where the second container comprises an outer housing and an inner container, pressurized gas is located in the inner container with the second liquid.
An advantage of the invention is that it is possible to introduce the additive into the first liquid without requiring direct handling of the propellant fluid or the additive by a user.
The conduit may contain a number of additives arranged at different positions along the length of the conduit. The additives may be liquid or solid in pourable form, such as powders or granules. The additives may be coloring agents, flavoring agents, fragrances, pharmaceutical components, chemicals, nutrients, liquids containing gases in solution etc.
The apparatus may comprise two or more conduits, each having a first end communicating with the second container and a second end communicating with the first container. Each conduit may contain a corresponding additive. The conduits may be of different lengths and/or cross-sectional areas. In this way a number of additives in different doses may be added to the liquid. If the dimensions of the conduit are accurately known, then the doses will be accurate.
The or each conduit may be provided with a one-way valve at the end of the conduit remote from the second container.
According to a second aspect of the present invention there is provided an apparatus for introducing a component into a first liquid, the apparatus comprising:
a first container for holding the first liquid having an opening closed by a releasable closure;
a releasable closure adapted to close said opening; and an insert located adjacent to said opening;
wherein said first chamber is provided with openings to allow the passage of said first liquid through said insert;
wherein the releasable closure comprises an integral closure container containing a propellant fluid;
wherein said insert comprises a first chamber for receiving said integral closure container and a hollow rupturing member extending into said first chamber and defining a second chamber inside said rupturing member;
wherein said closure container includes a rupturable member adapted to be ruptured by said rupturing member; and wherein
the apparatus further comprises a conduit having a first end communicating with the second chamber and a second end communicating with the first container, the conduit containing an additive which is expelled from the conduit into the first liquid by the entry of the propellant fluid into the conduit on release of the releasable closure.
The conduit or dip tube stores the additive product until it is fired by pressure of the propellant in the integral closure container or tank, and is forced out of the dip tube into the first liquid in the first container.
Preferably said closure container comprises a substantially tubular wall portion extending from said closure and a cap member sealingly fitted to said wall portion to form said closure container, wherein said cap member comprises said rupturable member.
Preferably on closing of the first container by the closure, the closure container is moved towards the rupturing member, such that when the closure container is in the closed position, the rupturable member is ruptured by the rupturing member and the contents of the closure container are prevented from being released from the closure container by the sealing action between the rupturing member and the cap member.
Preferably the cap member comprises a flange portion adapted to engage with the free end of the tubular portion of the closure member, by a rib and groove snap fit or similar. Preferably the cap member comprises a cylindrical bore portion adapted to receive and sealingly engage with a cylindrical portion of the rupturing member. Preferably the cylindrical bore portion is provided with upper and lower sealing ribs adapted to sealingly engage with the rupturing member.
Preferably the rupturing member includes one or more fluid ports through which the fluid passes when the closure container is moved away from the rupturing member on removal of the removable closure. Preferably said fluid ports are radial ports positioned such that in the closed portions the ports are located between the upper and lower sealing ribs of the cap member. Preferably the ports are positioned such that the distance between the ports and the upper end of the cylindrical portion of the rupturing member is less than the distance between the upper and lower sealing ribs, so that on removal of the removable closure the seal between the upper sealing rib and the cylindrical portion of the rupturing member is broken before the ports pass the lower sealing rib.
The preferred form of conduit or dip tube is a polypropylene tube of circular cross-section, typically having an internal diameter of 5.8 mm. Such a tube has an internal capacity of 0.26 ml for each 10 mm length, so an 80 mm long tube can hold approximately 2 ml of product. The tank typically has a capacity of 2 ml, and contains pressurized propellant gas.
When the tank is of an impermeable material such as metal, then the headspace required for the propellent gas is only a proportion of the total tank volume, leaving the remainder of the tank volume available for product.
However when the tank is of a material such as plastic which exhibits long term permeability, then the headspace required for the propellent gas must be maximised, and none of the tank volume is available for product. In such cases it can be necessary to use larger diameter dip tubes capable of holding more product, and there may then a need for a valve arrangement at the lower end of the dip tube so that product does not drip into the first liquid in the first container. The use of small diameter dip tubes such as capillary tubes avoids the need for valves, but such small diameter dip tubes can only hold a small amount of product.
The invention therefore also provides a simple, inexpensive valve arrangement which prevents the product in a dip tube from leaking or dripping into the first liquid in the first container when the dip tube and first container are at the same pressure, but which allows the passage of liquid or pourable solid product from the dip tube into the first liquid in the first container when the dip tube is pressurized by introduction of the propellant fluid. It should be emphasised that such a valve arrangement will not always be required.
Preferably the apparatus according to the first or second aspect of the invention is provided with a valve at the second end of the conduit member.
According to a first preferred embodiment the valve comprises an expandable tubular member and a sleeve member surrounding at least a portion of said expandable tubular member, wherein the expandable tube member has a closed end and at least one aperture therein adapted to permit the expulsion of fluid under pressure from the expandable tube member, and is expandable between a first unexpanded state in which the aperture is closed by contact with either the sleeve or a part of the expandable tubular member and a second expanded state in which the aperture is open.
Preferably the expandable tubular member is of plastic, most preferably of polypropylene. Preferably the sleeve is of plastic, most preferably of polypropylene. Preferably the tubular member and sleeve are both of circular cross-section.
Preferably the expandable tubular member comprises a corrugated portion adapted to concertina between said unexpanded and expanded states. Preferably said corrugated portion comprises a plurality of concertina-like ribs, each rib comprising a length of tube of increasing cross-sectional area and a length of tube of decreasing cross-sectional area. Preferably said sleeve comprises an inwardly directed flange at its upper end remote from the closed end of the expanded tubular member, adapted to engage with a corrugated portion of the expanded tubular member.
There may be provided more than one aperture, arranged circumferentially around the expandable tubular member.
According to a first aspect of the first preferred embodiment the aperture is provided in a concertina-like rib of said corrugated portion, most preferably in the lower rib adjacent to the closed end of the expandable tubular member. Preferably the lower rib is of larger external diameter than the upper ribs and is adapted to seal against the internal surface of the sleeve. Preferably the closed end of the expandable tubular member is formed by heat sealing.
According to a second aspect of the first preferred embodiment the aperture is provided in a uniform diameter portion of the expandable tubular member. Preferably the sleeve comprises an upper portion of larger diameter which fits around the corrugated portion of the expandable tubular member and a lower portion of smaller diameter which fits sealingly around the uniform diameter portion of the expandable tubular member. Preferably the closed end of the expandable tubular member is formed by an insert, preferably a concave insert, fixed inside the tubular member below the aperture.
According to a second preferred embodiment the valve comprises an expandable tubular member, as in the first preferred embodiment, but the sleeve member is omitted. In this case the resilience of the material of the expandable tubular member causes it to remain in the unexpanded state so that the aperture is closed by contact with a part of the expandable tubular member until internal pressure is applied to the expandable tubular member.
According to a third preferred embodiment the valve comprises a hollow tubular member having a flattened end portion of resilient plastics material, the flattened end portion comprising two opposing walls held in contact with each other by the resilience of the plastics material and adapted to move out of contact with each other when the hollow tubular member is subject to internal pressure.
Preferably the flattened end portion is formed by applying heat to the tubular member. Preferably the heat is sufficient to cause plastic deformation of the material, but not sufficient to cause melt bonding of the opposing walls.
The two opposing walls may be substantially planar. Alternatively the two opposing walls may be arcuate in transverse section, the outer surface of a first one of the opposing walls being in contact with the inner surface of the second one of the opposing walls.
The flattened end portion may comprise one or more transverse folds. Alternatively the flattened end portion may be curved or bent about a transverse axis. The flattened end portion may be rolled about a transverse axis.
Preferably the tubular member is of plastic, most preferably of polypropylene. Preferably the tubular member is of circular cross-section.
According to a third aspect of the invention there is provided a method of introducing an additive in the form of a liquid or granulated solid into a liquid, comprising introducing a predetermined quantity of the additive into a conduit at least partially closed at one end, installing the conduit in a vessel containing a liquid, closing the vessel, and triggering a pressure release apparatus upon opening the vessel, thereby forcing propellant into the open end of said conduit and expelling the additive from the partially closed end of the conduit into the liquid.
Preferably the method uses the apparatus according to the first or second aspects of the invention.